The effect of increased intra-abdominal pressure on orbital subarachnoid space width and intraocular pressure

• Published in: Neural regeneration research Vol. 13; no. 2; pp. 353 - 359
• Main Authors: Liu, Su-meng, Wang, Ning-li, Zuo, Zhen-tao, Chen, Wei-wei, Yang, Di-ya, Li, Zhen, Cao, Yi-wen
• Format: Journal Article
• Language: English
• Published: India Wolters Kluwer India Pvt. Ltd 01.02.2018; Medknow Publications and Media Pvt. Ltd; Medknow Publications & Media Pvt. Ltd; Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China,Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing, China%State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China%Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China; Medknow Publications & Media Pvt Ltd; Wolters Kluwer Medknow Publications
• Subjects: Abdomen; Care and treatment; Glaucoma; Intraocular pressure; Magnetic resonance imaging; Meninges; nerve regeneration; intraocular pressure; intra-abdominal pressure; intracranial pressure; trans-lamina cribrosa pressure difference; orbital subarachnoid space width; magnetic resonance imaging; optic nerve sheath; glaucoma; cerebrospinal fluid pressure; subarachnoid space; neural regeneration; Neurological research; Optic nerve; Peritoneal cavity; Physiological aspects; Software; Ultrasonic imaging; 空间宽度;压力差;轨道;神经病;基线值;可膨胀;声成像;公里; United States > US; magnetic resonance imaging; trans-lamina cribrosa pressure difference; neural regeneration; intracranial pressure; intraocular pressure; subarachnoid space; glaucoma; intra-abdominal pressure; nerve regeneration; optic nerve sheath; cerebrospinal fluid pressure; orbital subarachnoid space width; suba
• ISSN: 1673-5374; 1876-7958
• DOI: 10.4103/1673-5374.226407

In accordance with the trans-lamina cribrosa pressure difference theory, decreasing the trans-lamina cribrosa pressure difference can re- lieve glaucomatous optic neuropathy. Increased intracranial pressure can also reduce optic nerve damage in glaucoma patients, and a safe, effective and noninvasive way to achieve this is by increasing the intra-abdominal pressure. The purpose of this study was to observe the changes in orbital subarachnoid space width and intraocular pressure at elevated intra-abdominal pressure. An inflatable abdominal belt was tied to each of 15 healthy volunteers, aged 22-30 years （12 females and 3 males）, at the navel level, without applying pressure to the abdomen, before they laid in the magnetic resonance imaging machine. The baseline orbital subarachnoid space width around the optic nerve was measured by magnetic resonance imaging at 1, 3, 9, and 15 mm behind the globe. The abdominal belt was inflated to increase the pressure to 40 mmHg （1 mmHg = 0.133 kPa）, then the orbital subarachnoid space width was measured every 10 minutes for 2 hours. After removal of the pressure, the measurement was repeated 10 and 20 minutes later. In a separate trial, the intraocular pressure was measured for all the subjects at the same time points, before, during and after elevated intra-abdominal pressure. Results showed that the baseline mean orbital subarachnoid space width was 0.88 ＋ 0.1 mm （range： 0.77-1.05 mm）, 0.77 ＋ 0.11 mm （range： 0.60-0.94 mm）, 0.70 ＋ 0.08 mm （range： 0.62-0.80 ram）, and 0.68 _＋ 0.08 mm （range： 0.57-0.77 mm） at 1, 3, 9, and 15 mm behind the globe, respectively. During the elevated intra-abdominal pressure, the orbital subarachnoid space width increased from the baseline and dilation of the optic nerve sheath was significant at 1, 3 and 9 mm behind the globe. After decompression of the abdominal pressure, the orbital subarachnoid space width normalized and returned to the baseline value. There was no significant difference in the intraocular pressure before, during and after the intra-abdominal pressure elevation. These results verified that the increased intra-abdominal pressure widens the orbital subarachnoid space in this acute trial, but does not alter the intraocular pressure, indicating that intraocular pressure is not affected by rapid increased in- tra-abdominal pressure. This study was registered in the Chinese Clinical Trial Registry （registration number： ChiCTR-ONRC-14004947）.